I am contacting you as the only child of the mathematician Aurel Wintner (1903-1958), whose monograph “Spektraltheorie der Unendlichen Matrizen” you most kindly have added to your collection. My father published well over 400 papers and monographs in addition to his books. Nearly all of this material appeared in well-known journals and is easily available. However, during and shortly after WWII he independently published 4 monographs that only were distributed by mail to those who requested copies. It occurred to me, therefore, that these 4 items would be worth contributing to Internet Archive as well, along with the Spektraltheorie, which had gone out of print. As in that case, so with these — as a chemist I cannot actually judge this material, but from the comments of mathematician friends I believe that all of it is highly original. My father held the copyright to each; there was no publisher or journal involved; and I inherited all of his copyrights. Thus, there is no problem along those lines.